Stereo image display device and method

ABSTRACT

A stereo image display device includes an image display unit for displaying a parallactic image having a right-eye image and a left-eye image on a display plane, a parallactic image selecting unit for making only the right-eye image of the parallactic image reach the right eye of a viewer and making only the left-eye image of the parallactic image reach the left eye of the viewer to thereby make the viewer view a stereo image, an eye fatigue degree detecting unit for detecting the eye fatigue degree of the viewer, and an eye fatigue relaxation processing unit for carrying out eye fatigue relaxation processing for relaxing the eye fatigue of the viewer.

BACKGROUND

1. Technical Field

The present invention relates to stereo image display device and method.

2. Related Art

An image viewed through the right eye of a human and an image viewedthrough the left eye of the human are combine with each other in thebrain of the human, whereby the human recognizes the viewed object as astereo image. This is possible because the same object is viewed atdifferent angles (i.e., from different positions) by the right and lefteyes and thus the image viewed by the right eye and the image viewed bythe left eye are slightly different from each other.

Therefore, in order to make a viewer recognize a two-dimensionallydisplayed image as a stereo image, a parallactic image comprising animage to be viewed by the right eye (right-eye image) and an image to beviewed by the left eye (left-eye image) is displayed on thetwo-dimensional plane, and only the right-eye image is made to reach theright eye of the viewer while only the left-eye image is made to reachthe left eye of the viewer, whereby the viewer can recognize thetwo-dimensional parallactic image as a stereo image.

Specifically, a stereo image display device is equipped with an imagedisplay unit for displaying a parallactic image on a display plane, anda parallactic image selecting unit for making only the right-eye imageof the parallactic image reach the right eye of a viewer and making onlythe left-eye image of the parallactic image reach the left eye of theviewer. A pair of glasses may be used as the parallactic image selectingunit, for example. The viewer puts on the glasses concerned to therebyrecognize a stereo image. As the glasses may be generally used polarizedglasses having right-eye and left-eye transmissible portions thattransmit therethrough polarized light beams of different polarizationdirections, or liquid crystal shutter glasses having right-eye andleft-eye transmissible portions that are alternately varied between atransmissible state and a non-transmissible state. In the case of use ofthe polarized glasses, the right-eye image of the parallactic image isset to be based on the polarized light having the polarization directionalong which the right-eye transmissible portion transmits light, and theleft-eye image of the parallactic image is set to be based on thepolarized light having the polarization direction along which theleft-eye transmissible portion transmits light, whereby only theright-eye image is made to reach the right eye of the viewer and onlythe left-eye image is made to reach the left eye of the viewer.Furthermore, in the case of use of the liquid crystal shutter glasses,the right-eye image of the parallactic image is displayed under thestate that the right-eye transmissible portion is set to thetransmissible state and the left-eye transmissible portion is set to thenon-transmissible state, and the left-eye image of the parallactic imageis displayed under the state that the right-eye is set to thenon-transmissible state and the left-eye transmissible portion is set tothe transmissible state, whereby only the right-eye image is made toreach the right eye of the viewer and only the left-eye image is made toreach the left eye of the viewer.

Furthermore, there is known a stereo image display device using alenticular lens as a parallactic image selecting unit. Specifically, alenticular lens is disposed on a display plane so that only theright-eye image of a parallactic image displayed on the display plane isguided to the right eye of a viewer, and only the left-eye image of theparallactic image displayed on the display plane is guided to the lefteye of the viewer.

The stereo image display devices described above are disclosed inJP-A-63-70284 or JP-A-63-227193, for example.

In the stereo image display devices as described above, a viewer is madeto view a stereo image which does not actually exist, and thus theviewer's convergence and the focal point are not coincident with eachother, so that the viewer feels uncomfortable and suffers eye fatigue.

Particularly, when the viewer views a stereo image for a long time, alarge load is imposed on the viewer's eyes and the eye fatigue isintensified.

SUMMARY

An advantage of some aspects of the invention is to reduce eye fatigueof a viewer when the viewer views a stereo image.

In order to attain the above object, according to a first aspect of theinvention, a stereo image display device including an image display unitfor displaying a parallactic image having a right-eye image and aleft-eye image on a display plane, a parallactic image selecting unitfor making only the right-eye image of the parallactic image reach theright eye of a viewer and making only the left-eye image of theparallactic image reach the left eye of the viewer to thereby make theviewer view a stereo image, an eye fatigue degree detecting unit fordetecting the eye fatigue degree of the viewer, and an eye fatiguerelaxation processing unit for carrying out eye fatigue relaxationprocessing for relaxing the eye fatigue of the viewer.

According to the stereo image display device of the first aspect of theinvention, the eye fatigue degree of the viewer is detected by the eyefatigue degree detecting unit, and the eye fatigue relaxation processingis carried out in accordance with the detection result by the eyefatigue relaxation processing unit.

Therefore, even when the viewer views a stereo image for a long time,the load imposed on the viewer's eyes can be reduced as compared withthe stereo image display devices of the related art. Accordingly, thestereo image display device of the first aspect of the invention canreduce the eye fatigue of the viewer when the viewer views a stereoimage.

In the above stereo image display device, it is preferable that the eyefatigue degree detecting unit comprises plural image pickup units forpicking up images of the viewer, a calculating unit for calculating thedistance between the viewer's irises and the distance from the viewer tothe display plane on the basis of the image pickup results of the imagepickup units, a digitizing unit for digitizing an eye fatigue degree ofthe viewer per unit time in accordance with the distance between theviewer's irises and the distance from the viewer to the display plane,and an integrating unit for integrating the digitized eye fatigue degreeof the viewer per unit time and outputting a start signal of the eyefatigue relaxation processing as the detection result when theintegrating result exceeds a predetermined threshold value.

In the stereo image display device described above, it is preferablethat the eye fatigue relaxation processing unit may carry out as the eyefatigue relaxation processing the processing of displacing the stereoimage viewed by the viewer in a vertical direction to the display plane.

With the above construction, the stereo image is displaced in thevertical direction to the display plane in the eye fatigue relaxationprocessing, and thus the eye convergence of the viewer can be varied inaccordance with the displacement of the stereo image. That is, theviewer can make an eye stretch in the eye fatigue relaxation processing,so that the viewer's eye fatigue when the viewer views the stereo imagecan be reduced.

Furthermore, in the stereo image display device described above, it ispreferable that the eye fatigue relaxing unit is equipped with a displayplane displacing unit for displaying the display plane in the depthdirection with respect to the viewer, and the eye fatigue relaxationprocessing contains the processing of displaying the display plane.

With the above construction, the display plane is displaced in the depthdirection with respect to the viewer in the eye fatigue relaxationprocessing, and in connection with this displacement, the focal point ofthe eyes of the viewer can be varied. That is, the eyes of the viewercan be stretched in the eye fatigue relaxation processing, and the eyefatigue of the viewer can be reduced when a stereo image is viewed.

It is preferable that when the display plane is displaced, the displayplane is displaced without varying the size of the stereo image viewedby the viewer. Accordingly, the eye fatigue of the viewer when theviewer views a stereo image can be reduced without varying the size ofthe stereo image viewed by the viewer.

Furthermore, in the stereo display image described above, it ispreferable that the eye fatigue relaxing unit emit an alarm to theviewer in the eye fatigue relaxation processing.

With the above construction, an alarm is emitted to the viewer as theeye fatigue relaxation processing. Therefore, the moderation of the eyefatigue can be promoted to the viewer although it is not directlycarried out.

Next, according to another aspect of the present invention, a stereoimage display method comprises: displaying a parallactic imagecomprising a right-eye image and a left-eye image on a display plane;making only the right-eye image of the parallactic image to the righteye of a viewer while making only the left-eye image of the parallacticimage to the left eye of the viewer, thereby making the viewer view astereo image; and detecting an eye fatigue degree of the viewer andrelaxing the eye fatigue of the viewer in accordance with the detectionresult to carry out eye fatigue relaxation processing.

According to the stereo image display method described above, the eyefatigue degree of the viewer is detected, and the eye fatigue relaxationprocessing is carried out in accordance with the detection result.

Therefore, even when the viewer views a stereo image for a long time,the load imposed on the eyes of the viewer can be reduced as comparedwith the stereo image display device of the related art. Accordingly,according to the stereo image display method of the aspect of theinvention, the eye fatigue of the viewer when the viewer views a stereoimage can be reduced.

BRIEF DESCRIPTION FO THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic diagram showing a stereo image display deviceaccording to a first embodiment of the invention.

FIG. 2 is a diagram showing the operation of the stereo image displaydevice of the first embodiment of the invention.

FIG. 3 is a diagram showing the operation of the stereo image displaydevice of the first embodiment of the invention.

FIG. 4 is a diagram showing the operation of the stereo image displaydevice of the first embodiment of the invention.

FIG. 5 is a diagram showing the operation of the stereo image displaydevice of the first embodiment of the invention.

FIG. 6 is a schematic diagram showing a stereo image display deviceaccording to a second embodiment of the invention.

FIG. 7 is a schematic diagram showing a stereo image display deviceaccording to a third embodiment of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of stereo image display device and method according to theinvention will be described hereunder with reference to the accompanyingdrawings. In the drawings, the contraction scale of each element isproperly changed so that each element is visually recognizable.

First Embodiment

FIG. 1 is a schematic diagram showing the construction of a stereo imagedisplay device S1 of a first embodiment. As shown in FIG. 1, the stereoimage display device S1 of this embodiment comprises an image displaydevice 1 (image display unit) and glasses 2 (parallactic image selectingunit).

The image display device 1 displays a parallactic image comprising animage for a right eye (right-eye image) and an image for a left eye(left-eye image). This image display device 1 comprises a calculator 11(calculating unit), a digitizer 12 (digitizing unit), an integrator 13(integrating unit), an eye fatigue relaxation processor 14 (eye fatiguerelaxation processing unit), a parallactic image processor 15, aleft-eye image projector 16, a right-eye image projector 17, a firstimage pickup device 18 (image pickup unit), a second image pickup device19 (image pickup unit) and a screen 20 (display plane). The first imagepickup device 18, the second image pickup device 19 and the screen 20are disposed so as to face a viewer (the glasses 2).

The first image pickup device 18 and the second image pickup device 19are arranged in the horizontal direction, and it picks up the image ofthe viewer and outputs the image pickup result. By picking up the imageof the viewer with the two image pickup devices thus arrangedhorizontally, the images of the viewer which are picked up by therespective image pickup devices 18, 19 are slightly different from eachother.

On the basis of the image pickup result of the first image pickup device18 and the second image pickup device 19, the calculator 11 calculatesthe distance between the viewer's irises on the image pickup result ofthe first image pickup device 18 and the second image pickup device 19and the distance from the viewer to the screen 20. Here, as describedabove, the first and second image pickup devices 18 and 19 are arrangedso as to be slightly displaced from each other in the horizontaldirection, and thus the calculator 11 can easily calculate the distancefrom the viewer to the screen 20 on the basis of the displacement amountof the image pickup result of the image pickup devices 18, 19.Furthermore, the distance between the viewer's irises can be easilyachieved by actually measuring the corresponding distance on the imagepickup result of the first image pickup device 18 or/and the secondimage pickup device 19.

The digitizer 12 digitizes the eye fatigue degree per unit time inaccordance with the calculation result of the calculator 11, that is,the distance between the viewer's irises and the distance from theviewer to the screen 20.

For example, the distance to the gaze point is uniquely calculated onthe basis of the distance between the viewer's irises on the imagepickup result of the first image pickup device 18 and the second imagepickup device 19 and the distance from the viewer to the screen 20.Accordingly, the digitizer 12 stores the relationship of the distancebetween the viewer's irises on the image pickup result of the firstimage pickup device 18 and the second image pickup device 19 and thedistance from the viewer to the screen 20 and the gaze point distance inadvance and extracts a prescribed gaze point distance from thecalculation result of the calculator 11. The gaze point distance meansthe distance from the viewer to the stereo image viewed by the viewer,that is, the distance from the viewer to the position at which theviewer gazes. The digitizer 12 stores the eye fatigue degreecorresponding to the inverse number of each gaze point distance in theform of a numerical value in advance, and on the basis of thecalculation result of the calculator 11, the digitizer 12 can calculatethe eye fatigue degree of the viewer per unit time as a numerical value(i.e., digitize the eye fatigue degree).

The integrator 13 integrates the digitized viewer's eye fatigue per unittime, and outputs a start signal representing the start of the eyefatigue relaxation processing to the eye fatigue relaxation processor 14when the integration result exceeds a predetermined threshold value.

In the stereo image display device S1 of this embodiment, the eyefatigue detecting unit comprises the first image pickup device 18, thesecond image pickup device 19, the calculator 11, the digitizer 12 andthe integrator 13. That is, in the stereo image display of thisembodiment, the eye fatigue degree of the viewer is detected by thefirst image pickup device 18, the second image pickup device 19, thecalculator 11, the digitizer 12 and the integrator 13 constituting theeye fatigue detecting unit, and when the viewer's eye fatigue degreeexceeds the predetermined threshold value, the start signal representingthe start of the eye fatigue relaxation processing is output as adetection signal to the eye fatigue relaxation processor 14.

The eye fatigue relaxation processor 14 carries out the eye fatiguerelaxation processing for relaxing the eye fatigue of the viewer inaccordance with the start signal input from the integrator 13, that is,the detection result of the eye fatigue detecting unit. In thisembodiment, the eye fatigue relaxation processing is the processing ofdisplacing the stereo image viewed by the viewer in the verticaldirection to the screen 20. Specifically, the signal for the eye fatiguerelaxation processing is output to the parallactic image processor 15.On the basis of this signal, the signal of the parallactic image isconverted in the parallactic image processor 15 so that the stereo imageis displaced in the vertical direction to the screen 20. When the signalis input from the eye fatigue relaxation processor 14 to the parallacticimage processor 15, the parallactic image processor 15 converts thesignal of a parallactic image input from the external or the signal of aparallactic image stored in advance, and then inputs the parallacticimage signal thus converted to the left-eye image projector 16 and theright-eye image projector 17. However, when no signal is input from theeye fatigue relaxation processor 14, the parallactic image processor 15does not convert the signal of the parallactic image input from theexternal or the signal of the parallactic image stored in advance, anddirectly inputs the signal concerned to the left-eye image projector 16and the right-eye image projector 17.

The left-eye image projector 16 is supplied with the signal of theleft-eye image out of the parallactic image signal from the parallacticimage processor 15, and projects the left-eye image on the basis of thissignal to display the left-eye image on the screen 20.

Furthermore, the right-eye image projector 17 is supplied with thesignal of the right-eye image out of the parallactic image signal fromthe parallactic image processor 15, and projects the right-eye image onthe basis of this signal to display the right-eye image on the screen20.

The three-plate type liquid crystal projector using three liquid crystallight valves as optical modulators may be used as the left-eye imageprojector 16 and the right-eye image projector 17. Furthermore, asingle-plate type liquid crystal projector using a liquid crystal lightvalve as an optical modulator or a projector using a minute mirror arraydevice may be used.

As shown in FIG. 1, circular polarization plates 161 and 171 aredisposed at the subsequent stages of the left-eye and right-eye imageprojectors 16 and 17, respectively. These circular polarization plates161 and 171 polarize transmitted light in different rotationaldirections. In the stereo image display device S1 of the firstembodiment, the circular polarization plate 16 disposed at thesubsequent stage to the left-eye image projector 16 polarizes thetransmitted light to polarized light in a counterclockwise directionwhen viewed in the direction from the image display device 1 to theglasses 2, and the circular polarization plate 171 disposed at thesubsequent stage to the right-eye image projector 17 polarizes thetransmitted light to polarized light in a clockwise direction whenviewed in the direction from the image display device 1 to the glasses2.

The viewer puts on the glasses 2, and the glasses 2 have a right-eyetransmissible portion 21 for transmitting only image light of theright-eye image out of the parallactic image displayed on the screen 20,and a left-eye transmissible portion 22 for transmitting only imagelight of the left-eye image out of the parallactic image displayed onthe screen 20. The right-eye transmissible portion 21 and the left-eyetransmissible portion 22 are disposed so that the right-eyetransmissible portion 21 is disposed in front of the right eye of theviewer and the left-eye transmissible portion 22 is disposed in front ofthe left eye of the viewer when the viewer puts on the glasses 2.

Specifically, the glasses 2 of the stereo image display device S1 of thefirst embodiment are circular polarization glasses in which theright-eye transmissible portion 21 and the left-eye transmissibleportion 22 transmit circularly-polarized light beams different inrotational direction respectively. In the first embodiment, when viewedin the direction from the image display device 1 to the glasses 2, theright-eye transmissible portion 21 transmits only thecircularly-polarized light in the clockwise direction, and the left-eyetransmissible portion 22 transmits only the circularly-polarized lightin the counterclockwise direction.

The rotational direction of the circularly-polarized light is varied byreflection. Therefore, when the image light beams projected from theleft-eye image projector 16 and the right-eye image projector 17 arereflected in the image display device 1, the rotational direction of thepolarized light transmitted through each of the right-eye transmissibleportion 21 and the left-eye transmissible portion 22 is varied inaccordance with the reflection frequency. That is, the right-eyetransmissible portion 21 and the left-eye transmissible portion 22 areselected so that the image light emitted from the left-eye imageprojector 16 reaches only the left eye and the image light emitted fromthe right-eye image projector 17 reaches only the right eye.

Next, the operation of the stereo image display device S1 thusconstructed (stereo image display method) of this embodiment will bedescribed.

First, under a normal state, that is, when no start signal is input tothe eye fatigue relaxation processor 14 and thus no signal is input fromthe eye fatigue relaxation processor 14 to the parallactic imageprocessor 15, the signal of the parallactic image input from theexternal to the parallactic image processor 15 or the signal of theparallactic image stored in the parallactic image processor 15 inadvance is divided into the left-eye image signal and the right-eyeimage signal, and the left-eye and right-eye image signals thus achievedare input to the left-eye image processor and the right-eye imageprojector 17, respectively.

As a result, the left-eye image is projected from the left-eye imageprojector 16 onto the screen 20 and the right-eye image is projectedfrom the right-eye image projector 17 onto the screen 20.

Here, the image light of the left-eye image projected from the left-eyeimage projector 16 onto the screen 20 is polarized to polarized light inthe counterclockwise direction through the circular polarization plate161 when viewed in the direction from the image display device 1 to theglasses 2, and the image light of the right-eye image projected from theright-eye image projector 17 onto the screen 20 is polarized topolarized light in the clockwise direction through the circularpolarization plate 171 when viewed in the direction from the imagedisplay device 1 to the glasses 2.

In the stereo image display device S1 of this embodiment, the right-eyetransmissible portion 21 of the glasses 2 is constructed as a circularpolarization plate for transmitting only circularly-polarized light inthe clockwise direction when viewed in the direction from the imagedisplay device 1 to the glasses 2, and the left-eye transmissibleportion 21 of the glasses 2 is constructed as a circular polarizationplate for transmitting only circularly-polarized light in thecounterclockwise direction when viewed in the direction from the imagedisplay device 1 to the glasses 2. Therefore, the right-eye imagereaches only the right eye of the viewer, and the left-eye image reachesonly the left eye of the viewer. As a result, the brain of the viewercombines the right-eye image and the left-eye image, and the viewerviews the stereo image.

In the stereo image display device S1 of this embodiment, when theviewer views the stereo image, the image of the viewer is picked up bythe first image pickup device 18 and the second image pickup device 19.This image pickup result is input to the calculator 11. In thecalculator 11, the distance between the viewer's irises on the imagepickup result of the first image pickup device 18 and the second imagepickup device 19 and the distance from the viewer to the screen 20 onthe image pickup result are calculated. When the viewer views the stereoimage, the viewer puts on the glasses 2. In this case, the right-eyetransmissible portion 21 and the left-eye transmissible portion 22 areconstructed by polarization plates. Therefore, the distance between theviewer's irises can be checked on the image pickup result of the firstimage pickup device 18 and the second image pickup device 19.

Subsequently, the calculation result of the calculator 11, that is, thedistance between the viewer's irises on the image pickup result and thedistance from the viewer to the screen 20 is input to the digitizer 12.The digitizer 12 extracts the gaze point distance from the relationshipof the distance between the viewer's irises on the image pickup resultand the distance from the viewer to the screen 20 stored in advance andthe gaze point distance on the basis of the input calculation result.For example, when the distance from the viewer to the screen 20 which isbased on the input calculation result is equal to 1 m and therelationship between the distance between the viewer's irises on theimage pickup result for the distance of 1 m from the viewer to thescreen 20 and the gaze point distance is shown in a graph of FIG. 2, ifthe distance between the viewer's irises on the image pickup result ofthe input calculation result is equal to 6.2 cm, the calculator 11calculates the gaze point distance as 26 cm. Thereafter, the digitizer12 extracts the eye fatigue degree corresponding to the inverse numberof the gaze point distance which is digitized and stored in advance.Here, the inverse number of the gaze point distance is used because therelationship between the gaze point distance and the eye fatigue degreeis an inversely proportional relationship, that is, the eye fatiguedegree is increased as the gaze point distance approaches to zero.

As described above, the eye fatigue degree of the viewer is digitized onthe basis of the calculation result of the calculator 11 in thedigitizer 12.

The viewer's eye fatigue degree thus digitized is input to theintegrator 13. The integrator 13 integrates the viewer's eye fatiguedegree thus digitized and input and outputs the start signal to the eyefatigue relaxation processor 14 when the result exceeds a predeterminedthreshold value.

For example, the inverse number of the gaze point distance as shown inFIG. 3 varies with the time. That is, when a viewer views a stereo imagewhose pop amount from the screen 20 varies with the time, the integrator13 integrates the eye fatigue degree with the time lapse as shown inFIG. 4, and outputs the start signal when the integration result exceedsa threshold value E.

The start signal output from the integrator 13 is input to the eyefatigue degree relaxing processor 14. The eye fatigue relaxationprocessor 14 carries out the eye fatigue relaxation processing inresponse to the start signal thus input. Specifically, in the stereoimage display device S1 of this embodiment, as shown in FIG. 5, thestereo image viewed by the viewer is displaced in the vertical directionto the display plane of the screen 20. More specifically, the signal forconverting the parallactic image signal is output to the parallacticimage processor 15 so that the stereo image viewed by the viewer isdisplaced in the vertical direction to the display plane of the screen20. The parallactic image processor 15 converts the parallactic imagesignal is converted on the basis of the input signal.

As described above, by displaying the stereo image viewed by the viewerin the vertical direction to the display plane of the screen 20, theconvergence angle of the eyes of the viewer is varied, and thus the eyeof the viewer is stretched. Accordingly, the eye fatigue of the viewercan be reduced when the viewer views the stereo image.

Second Embodiment

Next, a second embodiment of the invention will be described. In thefollowing description of the second embodiment, the description of thesame portion as the first embodiment is omitted or simplified.

FIG. 6 is a schematic diagram showing the construction of a stereo imagedisplay device S2 of the second embodiment. As shown in FIG. 6, in thestereo image display device S2 of the second embodiment, the eye fatiguerelaxation processor 14 comprises a screen moving mechanism 141 (displayplane displacing unit).

The screen moving mechanism 141 moves (displaces) the screen 20 in thedepth direction with respect to the viewer.

In the stereo image display device S2 of this embodiment, when the startsignal is input to the eye fatigue relaxation processor 14, the eyefatigue relaxation processor 14 moves the screen 20 in the depthdirection with respect to the viewer by the screen moving mechanism 141.

By moving the screen 20 in the depth direction with respect to theviewer as described above, the focal length of the eyes of the viewerand the convergence angle of the eyes of the viewer are varied and theeyes of the viewer are stretched. Accordingly, the eye fatigue of theviewer when the viewer views the stereo image can be reduced.

In the stereo image display device S2 of the second embodiment, it ispreferable that the parallactic image signal is converted so that thesize of the stereo image viewed by the viewer is not varied when thescreen 20 is moved. Specifically, when the screen 20 is far away fromthe viewer, the right-eye image and the left-eye image are greatlyvaried, and when the screen 20 approaches to the viewer, the right-eyeimage and the left-eye image are slightly varied, so that the screen 20can be moved without varying the size of the stereo image viewed by theviewer. In this case, the convergence angle of the eyes of the viewer isnot varied, however, the focal length of the eyes of the viewer isvaried. Therefore, the eyes of the viewer can be likewise stretched, andthe eye fatigue of the viewer when the viewer views the stereo image canbe reduced.

Furthermore, in the stereo image display device S2 of the secondembodiment, when the parallactic image signal is converted so that thesize of the stereo image viewed by the viewer is not varied, it isunnecessary to electrically connect the eye fatigue relaxation processor14 and the parallactic image processor 15 to each other.

Third Embodiment

Next, a third embodiment of the invention will be described. In thefollowing description of the third embodiment, the description of thesame portion as the first embodiment is omitted or simplified.

FIG. 7 is a diagram showing the construction of a stereo image displaydevice S3 of the third embodiment. As shown in FIG. 7, in the stereoimage display device S3 of the third embodiment, the eye fatiguerelaxation processor 14 is equipped with an alarm portion 142.

When the start signal is input to the eye fatigue relaxation processor14, the alarm portion 142 emits an alarm to the viewer. Therefore, anoperation of relaxing the eye fatigue (for example, rest or the like)can be promoted to the viewer although it is not direct, so that the eyefatigue of the viewer can be reduced.

The alarm portion 142 may be performed by emitting an alarm ordisplaying an alarm message on the screen 20.

The embodiments of the stereo image display device and method accordingto the present invention have been described with reference to thedrawings, however, the invention is not limited to the above-describedembodiments. The shapes, combinations, etc. of the respectiveconstituent elements of the embodiments described above are examples,and various modifications in design, etc. may be modified withoutdeparting from the subject matter of the invention.

For example, in the above embodiments, the stereo image is moved, thescreen 20 is moved or the alarm is emitted as the eye fatigue relaxationprocessing. However, the invention is not limited to these manners. Forexample, the processing of displaying an image for relaxing the eyefatigue on the screen 20 or the processing of non-displaying the imageitself may be carried out as the eye fatigue relaxation processing.

In the above embodiments, the image of the viewer is picked up by theimage pickup devices 18 and 19, the distance between the viewer's iriseson the image pickup result and the distance from the viewer to thescreen 20 are calculated on the basis of the image pickup result, andthe eye fatigue degree of the viewer is detected on the basis of thecalculation result. However, this invention is not limited to thismanner. For example, the eye fatigue degree may be detected from otherecological information, or the eye fatigue degree of the viewer may bedetected by judging whether the eye fatigue degree of the viewer exceedsa threshold value when a predetermined time elapses.

Furthermore, in the above embodiments, the polarized glasses 2 using thecircular polarization plates as the right-eye transmissible portion 21and the left-eye transmissible portion 22 are used as the parallacticimage selecting unit. However, this invention is not limited to thismode. For example, liquid crystal glasses using liquid crystal shuttersas the right-eye transmissible portion 21 and the left-eye transmissibleportion 22 may be used as the parallactic image selecting unit.Furthermore, a lenticular lens or the like disposed on the screen 20 maybe used as the parallactic image selecting unit. In this case, it isunnecessary for the viewer to put on the glasses, and thus the image ofthe irises of the viewer can be more clearly picked up by the imagepickup devices 18 and 19.

In the above embodiments, the projector is used as the display unit fordisplay an image. However, the invention is not limited to this mode.For example, various kinds of displays such as a CRT, a liquid crystaldisplay device, a plasma display panel, an organic EL display device, aninorganic EL display device, a field emission device, asurface-conduction electron emitter display, etc. may be used.

The entire disclosure of Japanese Patent Application No. 2005-085835,filed Mar. 24, 2005 is expressly incorporated by reference herein.

1. A stereo image display device comprising: an image display unit fordisplaying a parallactic image having a right-eye image and a left-eyeimage on a display plane; a parallactic image selecting unit for makingonly the right-eye image of the parallactic image reach the right eye ofa viewer and making only the left-eye image of the parallactic imagereach the left eye of the viewer to thereby make the viewer view astereo image; an eye fatigue degree detecting unit for detecting the eyefatigue degree of the viewer; and an eye fatigue relaxation processingunit for carrying out eye fatigue relaxation processing for relaxing theeye fatigue of the viewer.
 2. The stereo image display device accordingto claim 1, wherein the eye fatigue degree detecting unit comprises:plural image pickup units for picking up images of the viewer; acalculating unit for calculating the distance between the viewer'sirises and the distance from the viewer to the display plane on thebasis of the image pickup results of the image pickup units; adigitizing unit for digitizing an eye fatigue degree of the viewer perunit time in accordance with the distance between the viewer's irisesand the distance from the viewer to the display plane; and anintegrating unit for integrating the digitized eye fatigue degree of theviewer per unit time and outputting a start signal of the eye fatiguerelaxation processing as the detection result when the integratingresult exceeds a predetermined threshold value.
 3. The stereo imagedisplay device according to claim 1, wherein the eye fatigue relaxationprocessing unit may carry out as the eye fatigue relaxation processingthe processing of displacing the stereo image viewed by the viewer in avertical direction to the display plane.
 4. The stereo image displaydevice according to claim 1, wherein the eye fatigue relaxationprocessing unit is equipped with a display plane displacing unit fordisplaying the display plane in the depth direction with respect to theviewer, and the eye fatigue relaxation processing contains theprocessing of displaying the display plane.
 5. The stereo image displaydevice according to claim 4, wherein the eye fatigue relaxationprocessing unit carries out the processing that the display plane isdisplaced without varying the size of the stereo image viewed by theviewer.
 6. The stereo display image according to claim 1, wherein theeye fatigue relaxation processing unit emits an alarm to the viewer inthe eye fatigue relaxation processing.
 7. A stereo image display methodcomprising: displaying a parallactic image having a right-eye image anda left-eye image on a display plane; making only the right-eye image ofthe parallactic image to the right eye of a viewer while making only theleft-eye image of the parallactic image to the left eye of the viewer,thereby making the viewer view a stereo image, wherein an eye fatiguedegree of the viewer is detected and the eye fatigue of the viewer isrelaxed in accordance with the detection result to carry out eye fatiguerelaxation processing.